Third (supernumerary) nipples are fairly common, and are found in men and women. They are generally not related to other medical conditions. The extra nipples usually occur below the normal nipples and tend to be small and not well formed. The nipples are along the two vertical "milk lines", which start in the armpit on each side, run down through the normal nipples and end at the groin.
...Read more

9

Simple bumps:
The Montgomery glands or tubercles surround the nipples in the pigmented area or areola. A third nipple will be in the "milk line" on the chest or even abdomen. These accessory nipples can be found usually below the primary nipples. The accessary nipples are usually smaller than the primary nipples whereas the Mongom. glands are very simple bumps.
...Read more